The present invention relates to systems for transferring articles in a manufacturing environment, and specifically to transferring semiconductor wafers, liquid crystal or flat panel displays and similar articles in a mini-environment.
Typical manufacturing environments include a variety of processing tools for each of the various stages of manufacture. Often a variety of products are produced in one manufacturing environment, where each product is manufactured according to a specific recipe. Where products are transported throughout the manufacturing environment in containers, it is ideal that such containers have a common interface with each of the processing tools. As manufacturing environments automate, it is desirable to coordinate each of the processing tools for efficient production. Typically, products are moved from one tool to the next by a human attendant or by a robot, according to a central plan. In some automated environments, a central controller is used to coordinate production. In each of these systems it is desirable to have a common interface and an effective means of communication within the manufacturing environment.
Particular type products often introduce specific requirements into the process. For example, integrated circuits, liquid crystal displays (LCDs) and other such articles require an extremely clean environment to prevent contaminants from rendering the articles unusable or unreliable. Integrated circuits specifically include miniature size features, where even a microscopic particle or contaminant can interfere with the proper operation of the integrated circuit and thereby directly impact the cost and yield of the integrated circuits. In such a manufacturing environment, cleanliness of the manufacturing environment is a key concern in fabricating integrated circuits.
Some of the specific production requirements of integrated circuit fabrication are addressed by the creation of a clean room to house the manufacturing environment. A traditional semiconductor clean room is created by enclosing processing tools in a controlled environment or enclosure. Prior to entry, personnel don special clothing to reduce the chance of contaminating the wafers. While clean rooms provide a clean manufacturing environment, they are expensive to construct, difficult to maintain, and inconvenient to operate. Additionally, as feature sizes reduce below one micron, clean rooms are no longer effective at preventing contamination.
As a step beyond the traditional clean room, the Standard Mechanical Interface (SMIF) systems enclose the processing tool in a controlled xe2x80x9cmini-environment.xe2x80x9d The mini-environment is to provide a particulate-free air space around the tool. A second controlled mini-environment is created within a wafer carrier, called a pod. The pod is a type of container used for transporting wafers from one processing tool to the next. In effect, a discontinuous clean room is created by the combination of tool mini-environments and the pod mini-environment. During processing, the pod is coupled to the tool mini-environment so as to prevent the introduction of contaminants to the wafers.
While SMIF type systems offer advantages over the conventional clean room, there is a further need to automate the manufacturing process and increase the flexibility of the interface between containers and processing tools. Additionally, there exists a general need for an automated transfer mechanism within a manufacturing environment, which provides a smooth method of interfacing the product containers with the processing tool, and which allows for improved communication between the transfer mechanism, the tool, the container and a main controller.
For interface with a variety of tools, it is often desirable that the container be presented in a variety of orientations, specific to the tool and container requirements. An apparatus and method are needed for smooth and efficient interface with processing tools in a manufacturing environment, having automated control and adaptation.